<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>prompt 提示对话框</title>
</head>
<body>
    <script>
        // let name = prompt("请输入一个人名");
        // alert(name);
        let num = Number.parseInt(prompt("请输入一个数字"));
        alert(num+1);
    </script>
</body>
</html>